This disclosure is directed to a unified fire extinguisher system for aircraft. It is particularly intended for aircraft provided with multiple engines and a fuselage located compartment, typically housing the flight crew, cargo, aviation equipment, passengers and the like. Fire protection systems in aircraft known heretofore can ideally be described as special hazard systems. For instance, a dedicated fire extinguisher system will be installed in proximity to an aircraft engine. Other protected areas may include a fuel tank, flight cabin, or some other piece of equipment deemed to be more of a fire hazard risk than the remainder of the aircraft. In some instances, it is known to utilize two containers of the extinguishant with an outlet valve for discharging one or more containers to a specific engine or area. The C5A military aircraft and Boeing 747 have systems which protect the cargo compartment. As will be appreciated, the term "cargo" applies both to aircraft configured to transport passengers and bulk cargo in the compartment area. This is usually a function of seating installed in the fuselage.
The present system (and apparatus) has an advantage over the equipment which is believed to characterize the prior art. The present apparatus utilizes multiple containers of extinguishant at a central location. They are much easier to service. Moreover, location of the several containers at a central location enables delivery of the extinguishant to a selected point where all of the available extinguishant might well be required. Consider the instance of a localized, but critical fire. The present invention is able to deliver extinguishant via a manifold system to the selected zone. If one container of extinguishant is exhausted, another can be brought onstream and also applied. Moreover, this can be accomplished without regard to the location of the alarm condition. This can be achieved by directing the extinguishant to an engine located at a wing-mounted position or other position such as a fuselage pylon or within the fuselage. It will function equally well if the fire hazard is created in the fuselage area or in an overhead engine compartment typified by the Laker aircraft,
The subject system operates under control of the pilot or co-pilot, the controls for same ordinarily being installed with a control panel equally convenient to all flight deck personnel. While the precise location may vary, the present apparatus offers to the crew a system whereby the extinguishant supply can be checked. Likewise, the system permits the checking or testing of the valves connected to the common manifold so that valve condition and operation is verified. Extinguisher verification can be incorporated in a preflight checklist so that equipment is confirmed operative before takeoff. This particularly has an advantage over equipment believed to be representative of the prior art. Known prior art systems are thought to be deficient in that they utilize valves which cannot be routinely tested or checked by flight deck crews, and many times hand-checking a valve connected to a fire extinguisher apparatus is difficult if not totally impractical to inspect. In most cases, the equipment will be in the armed or ready, but in a quiescent state for weeks, months or years, thereby making the possibility of a valve sticking a harsh reality. The present apparatus incorporates a means whereby the valve can be operated during preflight checkout, the operation confirming that the valve is either open or closed (as required) and further confirming that it is still operative so that it can switch to the desired state. This avoids the unwanted hazards and problems of known prior art equipment failures involving either a valve stuck either closed or open. If a valve is stuck open, it may well bleed off excessive quantities of extinguishant from the desired path of flow to distribute the extinguishant where no fire exists. Alternatively, if the valve is stuck shut, it may very well deny all extinguishant to the area where the fire is localized. In either case, the results are deemed to be catastrophic.